<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .box {
        width: 100px;
        height: 100px;
        background-color: cyan;
        /* border: 0.333333px solid red; */
      }

      /* 多媒体查询器 */
      @media screen and (-webkit-min-device-pixel-ratio: 2) {
        .box {
          border: 0.5px solid red;
        }
      }

      @media screen and (-webkit-min-device-pixel-ratio: 3) {
        .box {
          border: 0.333333px solid green;
        }
      }
    </style>
  </head>
  <body>
    <div class="box"></div>
  </body>
</html>
